In the midst of the opioid crisis, health workers are not only seeing firsthand the effects of addiction, abuse and accidental overdose—but they’re also on the front lines of America’s hepatitis C virus (HCV) epidemic. So why are so few drug treatment centers testing opioid and meth users for the virus? NPR’s Shots dived into the topic.

The report lists all the ways in which health care facilities that serve people who use drugs are well-positioned to initiate hep C testing: They’re often the first point of health care for opioid or meth users; they are experienced in working with hard-to-reach populations; and they often offer harm reduction services, like syringe exchanges, to help reduce new infections. However, studies show that drug users often go untested for HCV, which represents an enormous missed opportunity for finding and curing new infections.

Public health advocates say lack of money, staff and other resources stand in the way of testing and point out as well that potential clients are not necessarily interested in getting tested or treated.

Plus, if people test positive, they need to be linked to treatment and other care services, and financial support for staffing such services is often limited. Then there’s the matter of insurance. Many people who enroll in drug treatment programs are uninsured and cannot access expanded Medicaid under the Affordable Care Act where they live.

The result? In 2017, just 27.5 percent of 12,166 centers specializing in substance use disorders offered testing for hep C. Among federally certified methadone and other drug treatment clinics, the HCV testing rate, though higher, was just over 63 percent. When it comes to primary care settings, those between ages 13 and 21 diagnosed with opioid use disorder at federally qualified health centers were screened for hep C at a rate of only 36 percent, which is especially alarming given that HCV rates are growing fastest among this population.

Advocates call for the development of an entire system of hep C care just for drug users.